AB0071 PRE-CLINICAL EVALUATION OF ANTI-ANGIOGENIC EFFECTS OF CANDIDATE AGENTS FOR MOLECULAR DIAGNOSTIC IMAGING AND THERAPY IN RHEUMATOID ARTHRITIS
Authors: F. Khodadustvaskasi, E. Philippon, E. Mantel, J. P. Van Hamburg, J. Van Beijnum, A. D. Windhorst, G. Jansen, S. Tas, C. J. Van der Laken
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> The role of pathological angiogenesis is widely recognized in cancer and various inflammatory diseases, including rheumatoid arthritis (RA). In RA, angiogenesis and inflammation are mutually dependent and play a cooperative role in the disease progression. Angiogenesis mainly relies on the interaction of vascular endothelial cells (ECs), fibroblasts, macrophages, and the extracellular matrix. This phenomenon promotes the infiltration of inflammatory cells into the joints, resulting in more synovial inflammation and structural damage. In this process, a number of soluble and cell surface-bound angiogenic mediators are involved providing candidate targets for diagnosis and therapy [1, 2]. Anti-angiogenesis strategy has been widely used in tumor treatment and its potential value in RA as a single or in combination therapy need to be further explored. <h3>Objectives</h3> To assess potential anti-angiogenic effects of selected compounds with different mechanisms of action in preclinical models of angiogenesis for exploitation as candidate agents for molecular imaging and/or therapeutics purposes. <h3>Methods</h3> Two <i>in vitro</i> models of angiogenesis were employed in this study: (i) a scratch assay assessing the closure rate of scratches made in human microvascular endothelial cells (HMEC-1) [3] in the presence of drugs for 24 hr, and (ii) 3D-spheroid model of angiogenesis composed of ECs and fibroblasts, assessing the impact of drugs on EC sprout formation after 40 hr of incubation. Sprout quantification was performed via confocal microscopy and digital image analysis [2]. Candidate anti-angiogenic compounds examined in this study included: sunitinib (pan-kinase inhibitor), a small molecule NF-κB-inducing kinase inhibitor (NIKi), tofacitinib (selective JAK1/3 inhibitor) and fluciclatide (RGD-peptide targeting α<sub>V</sub>β<sub>3</sub> and α<sub>V</sub>β<sub>5</sub> integrins) and tested in concentration range of 0-10 μM. An MTT-proliferation inhibition assay was used to monitor any drug-induced cytotoxicity. <h3>Results</h3> In scratch assays, sunitinib exhibited irreversible inhibition (max 75% at 10 μM after 24 hr incubation) compared to NIKi which had a transient inhibitory effect (max 59% at 10 μM after 8 hr incubation). No apparent effects were observed for tofacitinib up to concentrations of 10 μM. Interestingly, fluciclatide, induced morphological changes at concentration of 0.1 μM, impairing scratch closures. Next, the anti-angiogenic effects of the compounds were verified in the 3D-spheroid model that more closely mimics the <i>in vivo</i> situation. Here, marked blockade of sprout formation was noted at 0.1 μM for sunitinib, and 1-2.5 μM for NIKi, tofacitinib and fluciclatide. MTT assays indicated that none of the observed drug-effects were due to induction of cytotoxicity at the indicated concentrations. <h3>Conclusion</h3> This study identified various compounds (sunitinib, NIKi, tofacitinib and fluciclatide) exhibiting potential anti-angiogenic properties <i>in vitro,</i> encouraging their further evaluation as radionuclide imaging and therapeutic agents for diagnosis and therapeutics in vivo. <h3>References</h3> [1]Khodadust, F., et al., Systematic Review: Targeted Molecular Imaging of Angiogenesis and Its Mediators in Rheumatoid Arthritis. Int J Mol Sci, 2022. 23(13). [2]Maracle, C.X., et al., Targeting non-canonical nuclear factor-kappaB signalling attenuates neovascularization in a novel 3D model of rheumatoid arthritis synovial angiogenesis. Rheumatology (Oxford), 2017. 56(2): p. 294-302. [3]Prigozhina, N.L., et al., Characterization of a novel angiogenic model based on stable, fluorescently labelled endothelial cell lines amenable to scale-up for high content screening. Biol Cell, 2011. 103(10): p. 467-81. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.